Automatic resuscitating apparatuses are used to supply an oxygen-containing gas to a patient. Such apparatuses include a pressurised source of the oxygen-containing gas (which we shall refer to hereinafter simply as `gas` and it may be air or air that has been enriched with oxygen or pure oxygen or indeed any other breathable oxygen-containing gas), a face mask and a control module which, when operating in an `automatic` mode, feeds pulses of the gas to the face mask to inflate the patient's lungs. The control module may sense the pressure of the gas in the mask (or in a line leading to the mask) and provide a pulse of gas when the pressure has fallen to a predetermined value. At the end of each pulse the patient exhales (during which time no gas is supplied); at the end of exhalation, the pressure in the mask has fallen to or below the threshold value and so another pulse of gas is supplied by the control module.
However, particularly in the case of patients who have suffered a heart attack, such automatic supply of pulses of gas should not be used and instead the control module should be switched to a `manual` mode of operation in which it provides a continuous supply of gas to a gas line containing a manually-operated valve or trigger; the valve controls the flow of gas in the gas supply line and can be closed to stop gas flow to allow the patient to exhale and opened to initiate flow again to inflate the patient's lungs.
Hitherto, a control module that is operable in both an automatic and a manual mode has required a separate face mask connected to a separate gas supply line for each mode of operation; thus, if the control module were being operated in the automatic mode supplying pulses of gas to a patient by way of the appropriate face mask and if it were then necessary to change over to manual control, the face mask and the supply line for the automatic mode of operation has to be taken off the patient and the mask and supply line for the manual mode of operation has to be fitted instead; simultaneously, it is necessary to switch the control module to supply a constant stream of gas to the second (manual) mask and to disconnect the source of gas to the first (automatic) mask. Since the control module may be out of easy reach of the medical personnel administering the resuscitation, the whole operation can be awkward, take vital time and interrupt the supply of gas to the patient and so, in an extreme case, could endanger the patient's life.